Navigation systems are widely used for vehicles. A navigation system identifies a current position of a vehicle or a user in real time by calculating coordinate signals received from Global Positioning System (referred to as ‘GPS’, hereinafter) satellites and indicates the current position onto a map image by interlocking the current position with the database with map information and traffic information built previously. The navigation system for a vehicle employs a GPS receiver to calculate a current position of a vehicle. The navigation system obtains information on current speed, time and position of the vehicle by virtue of the GPS receiver and provides a user with guidance information based on such information.
However, when calculating the current position using GPS signals, there normally occurs an error of tens of meters because of characteristics of the GPS signals, which results in that the navigation system displays the current position on an erroneous point, such as a position out of road or a building, on a map.
In order to avoid such a problem, a conventional navigation system applies a map matching method to calculate a position of the vehicle. According to the map matching method, a current position of a vehicle and road data are compared each other under the assumption that the vehicle is driving on the road. Further, when the difference between the current position and coordinate data is within a predetermined range, it is determined that the vehicle is driving on the road and the current position is forcibly corrected into a point on the road data nearest the current position.
Korean Laid-Open Patent No. 10-2010-0067578 suggests an apparatus and method for map matching of a moving object. The Korean Laid-Open Patent No. 10-2010-0067578 discloses a map matching method to correct a position coordinate of a moving object such as a vehicle moving on a road, wherein a position of the moving object is corrected into a point on the road when coordinate data of the road does not exist on a map data and thus it is not easy to make a conventional map matching.
Japanese Laid-Open Patent No. 2002-318121 discloses a navigation system, which is capable of determining a current position of a moving object when the moving object moves into an indoor facility. First, the navigation system determines a current position of the moving object by performing a map matching on an output data from a stand-alone sensor and an output data from a GPS apparatus using a map data while the moving object is moving. Thereafter, when it is detected that the current position of the moving object is located within an indoor facility, the navigation system performs a map matching on the output data from the stand-alone sensor using a map data to determine the current position of the moving object.
Generally, in case that positioning information of a user is received, a position of the user is displayed by making a map matching to road network data (node or link, for example) nearest to the position. However, in case that the user is placed at an indoor location, especially, at a specific space in a building, a positioning result is map-matched to the nearest network data, which results in that it is not possible to precisely reflect a real position of the user on the map.